Biodiesel produced from plant oil has drawn attention not only as a fuel substitution of fossil fuel but also as a substance exhibiting a decrease in carbon dioxide emission, and its demand has been expected to be increased. When the biodiesel fuel is produced, glycerin is produced as a by-product, and therefore, it is needed to use glycerin advantageously.
As one example of utilizing glycerin, there is a process for producing acrolein from glycerin as a starting material. For example, U.S. Pat. No. 1,916,743 discloses a process for producing acrolein by the use of pumice supporting lithium phosphate or copper phosphate as a catalyst, and Japanese Patent Laid-Open Publication No. 6-211724 discloses a process for producing acrolein by the use of a carrier supporting phosphoric acid as a catalyst. Further, French Patent No. 695,931 discloses a process for producing acrolein by the use of silica or alumina supporting lithium phosphate as a catalyst.
In the acrolein production by the use of a catalyst as described above, it is desired to suppress a decrease in the yield of acrolein, even when acrolein is produced by the continued use of a catalyst. If a decrease in the yield of acrolein can be suppressed, it is expected that acrolein derivatives such as acrylic acid, 1,3-propanediol, allyl alcohol, polyacrylic acid, and polyacrylates, which have heretofore been known to be produced from acrolein as a starting material, can be produced at low cost.